144 NOTES AND MEMORANDA. 



there are fertile workers, among which copulation is not observable, 

 and is perhaps even impossible for various reasons. They are well 

 proved and frequent amongst the wasps and Polistes ; to them is attri- 

 buted, among the drones, the considerable number of males which are 

 observed late in the autumn. They exist among certain species of ants, 

 notably Formica sanguinea. Fertile workers have been recognized 

 for a long time among bees ; but until recently these fertile workers, 

 as t: ey only laid male eggs, like the drone-bearing queens, conform- 

 ably to the Dzierzon theory, were thought to be very rare and 

 accidental. They are, on the contrary, frequent, and coexist with 

 the queen in a great number of hives. As in M. Perez's hive there 

 was a mixture of yellow, black, and hybrid workers, the fertility of 

 certain workers of the two last sorts is sufficient to explain the mix- 

 ture. An exclusive laying of black drones has even been found in the 

 case of an analogous hive.* More than this, a yellow Italian mother, 

 fecundated, not by a black male, but by a yellow Italian male of her 

 own race, being given, by artificial swarming, to an orphan colony of 

 black bees, not only numeroits yellow but also black drones appeared 

 after a certain time. These latter, M. Giard thinks, could only come 

 from fertile black workers ; " for, in order to find the black ancestors 

 of M. Sanson, it would be necessary to throw back the atavism into 

 the night of ages, farther perhaps than the bees of Virgil." To decide 

 this question irrefutably, we must employ the method of elimination, 

 and suitably separate the layings of the queen and of the fertile 

 workers. 



Hermaphroditism in Perlidse. — Dr. Alexander Brandt, of St. 

 Petersburg, describes "f" an interesting case of hermaphroditism in 

 certain of these orthopterous insects (Perla hipunctata, &c.), in which 

 he found undoubted ovaries in connection with the testes of male 

 larvae, both male and female glandular f Hides being developed as 

 out-pushings of one and the same excretory duct. 



Employment of Mixtures of Chromic and Osmic Acids for His- 

 tological Purposes. — Dr. Max Flesch recommends | this mixture in 

 the following proportions : — 



Osmic acid 0"10 



Chromic acid • 2.5 



Distilled water 100-00 



It answers particularly well for the auditory organs of smaller animals, 

 many of the details of structure of the cochlea coming out with quite 

 diagrammatic clearness. The hairs of the hair-cells are, however, 

 mostly lost. It also answers well for examining the growth of bone 

 in the epiphyses of small animals, and for general views of retina, con- 

 junctiva, cornea, and the eyelids ; in these latter many details suffer, 

 especially the bacillary layer of the retina. 



The objects for examination are placed fresh in the fluid, and kept 

 there from twenty-four to thirty-six hours. There is no need to keep 



* See the journal 'Apiculture,' August, 1878. 



t 'Zool. Anzeiger,' vol. i. (1878). 



X ' Archiv f. Mikr. Auat.,' vol. xvi. (1878). 



